feat: add a property to a json object (#50)

Streamistry.Core/JsonObjectPropertyAppender.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Text;
+using System.Text.Json.Nodes;
+using System.Threading.Tasks;
+using Json.More;
+using Json.Path;
+
+
+namespace Streamistry;
+public class JsonObjectPropertyAppender<TInputMain, TInputSecondary> : Zipper<TInputMain, TInputSecondary, TInputMain>
+    where TInputMain : JsonNode
+    where TInputSecondary : JsonNode
+{
+
+    public JsonObjectPropertyAppender(IChainablePort<TInputMain> mainUpstream, IChainablePort<TInputSecondary> secondUpstream, string path)
+        : base(mainUpstream, secondUpstream, (x, y) => AppendProperty(x, y, path))
+    { }
+
+    private static TInputMain? AppendProperty(TInputMain? main, TInputSecondary? secondary, string path)
+    {
+        if (main is null)
+            return null;
+        if (secondary is null)
+            return main;
+        var segments = path.Split('.');
+        AddOrReplaceProperty(main, string.Join('.',segments.Take(segments.Length - 1)), path.Split('.').Last(), secondary);
+        return main;
+    }
+
+    private static void AddOrReplaceProperty(JsonNode root, string jsonPath, string propertyName, JsonNode value)
+    {
+        var path = JsonPath.Parse(jsonPath);
+        var result = path.Evaluate(root);
+
+        if (result.Matches != null && result.Matches.Count > 0)
+        {
+            foreach (var match in result.Matches)
+            {
+                if (match.Value is JsonObject jsonObject)
+                    jsonObject[propertyName] = value;
+            }
+        }
+        else
+        {
+            CreatePathAndAddProperty(root, jsonPath, propertyName, value);
+        }
+    }
+
+    private static void CreatePathAndAddProperty(JsonNode root, string jsonPath, string propertyName, JsonNode value)
+    {
+        var segments = jsonPath.TrimStart('$').Split('.', StringSplitOptions.RemoveEmptyEntries);
+        JsonNode current = root;
+
+        foreach (var segment in segments)
+        {
+            if (current is JsonObject obj)
+            {
+                if (!obj.ContainsKey(segment))
+                {
+                    var newObject = new JsonObject();
+                    obj[segment] = newObject;
+                    current = newObject;
+                }
+                else
+                {
+                    current = obj[segment]!;
+                }
+            }
+            else
+            {
+                throw new InvalidOperationException("Invalid path or JSON structure.");
+            }
+        }
+
+        if (current is JsonObject finalObj)
+        {
+            finalObj[propertyName] = value;
+        }
+        else
+        {
+            throw new InvalidOperationException("Final path segment is not an object.");
+        }
+    }
+}

Streamistry.Core/JsonValueMapper.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json.Nodes;
+using System.Threading.Tasks;
+
+namespace Streamistry;
+public class JsonValueMapper<TInput> : Mapper<TInput, JsonValue>
+{
+    public JsonValueMapper(IChainablePort<TInput> upstream, Func<TInput?, string>? toString = null)
+        : base(upstream, value => toString is null ? JsonValue.Create(value) : JsonValue.Create(toString.Invoke(value)))
+    {
+    }
+}

Streamistry.Testing/JsonObjectPropertyAppenderTests.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json.Nodes;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using Streamistry.Pipes.Parsers;
+using Streamistry.Pipes.Sinks;
+using Streamistry.Pipes.Sources;
+
+namespace Streamistry.Testing;
+public class JsonObjectPropertyAppenderTests
+{
+    [Test]
+    public void X()
+    {
+        var persons = new EnumerableSource<string>([
+            JsonTests.JsonFirst, JsonTests.JsonSecond, JsonTests.JsonThird]);
+        var birthdates = new EnumerableSource<DateOnly>([new DateOnly(1879, 3, 14), new DateOnly(1856, 7, 10), new DateOnly(1903, 12, 28)]);
+        var pipeline = new Pipeline([persons, birthdates]);
+        var personObject = new JsonObjectParser(persons);
+        var birthdateValue = new JsonValueMapper<DateOnly>(birthdates, date => date.ToString("yyyy-MM-dd"));
+        var appender = new JsonObjectPropertyAppender<JsonObject, JsonValue>(personObject, birthdateValue, "$.user.birthdate");
+        var sink = new MemorySink<JsonObject>(appender);
+        pipeline.Start();
+
+        Assert.That(sink.State.Count, Is.EqualTo(3));
+        Assert.That(sink.State.First()!["user"]!["birthdate"], Is.Not.Null);
+        Assert.That(sink.State.First()!["user"]!["birthdate"]!.GetValue<string>(), Is.EqualTo("1879-03-14"));
+    }
+}

Streamistry.Testing/JsonTests.cs

@@ -15,7 +15,7 @@
 namespace Streamistry.Testing;
 public class JsonTests
 {
-    private const string JsonFirst = @"
+    public const string JsonFirst = @"
     {
         ""user"": {
             ""name"": ""Albert Einstein"",
@@ -27,7 +27,7 @@ public class JsonTests
         }
     }";
 
-    private const string JsonSecond = @"
+    public const string JsonSecond = @"
     {
         ""user"": {
             ""name"": ""Nikola Tesla"",
@@ -39,7 +39,7 @@ public class JsonTests
         }
     }";
 
-    private const string JsonThird = @"
+    public const string JsonThird = @"
     {
         ""user"": {
             ""name"": ""John von Neumann"",